IN Q1 2015 ALONE, Apple and Google separately announced they were investing more than $3bn in renewable energy projects in Europe and the US. Some are going further still with the eventual aim of operating carbon-neutral, and potentially even energy-neutral, facilities.
This article examines some of the main drivers and obstacles for powering datacentres with renewable energy and how this may impact the long-term design and operation of facilities.
The key challenges when it comes to increasing the use of grid and on-site renewable energy are the intermittent nature of renewables and the price of grid and on-site renewables compared with fossil fuels – at least in the short term. Financial mechanisms such as renewable energy certificates remain complex and open to criticism around their true environmental value. The continuing lack of carbon regulations is another factor. Despite these issues, an increasing number of operators see value in investing in renewables, and their actions may convince, or force, others to follow their lead.
Most datacentres will only derive a very small percentage, if any at all, of their energy from grid renewables. However, a number of Internet companies that own and operate very large hyperscale facilities report that as much as 100% of the energy powering certain facilities, and other infrastructure, such as offices and shops, is now derived from renewables.
For example, in Q1 2015, Apple said it was investing $1.9bn in two new European datacentres that will be 100% powered by renewables (grid and on-site). In the same period, Apple announced an $848m solar investment in California, while Google announced a significant wind turbine project in the same state. While other factors play a role, these organisations say they see clear financial benefits from investing in renewables, including significant government subsidies/tax breaks, as well as other ancillary benefits.
Investment in renewable energy is often also influenced by (actual or anticipated) regulation and reputational concerns. Regarding regulation, there has only been one serious attempt to put a price on datacentre carbon emissions – the UK CRC Energy Efficiency Scheme introduced in 2011, which was eventually scaled back, and then datacentres were given an exemption in 2014. However, the EU Energy Efficiency Directive (EED) introduced in 2012 requires organisations to produce accurate and approved reports on their total energy usage, which may also help drive adoption of renewables.
Grid renewables
A growing number of datacentres are investing in large-scale, on-site renewable projects. However, the majority of facilities are only able to access renewable energy from the grid due to the cost and complexity involved in on-site generation. However, grid-based renewable energy also has its own challenges:
Price – The price of grid-based renewable energy is an important factor in why it hasn’t been adopted more widely in the datacentre industry. Grid renewables are still more expensive on average than equivalent fossil fuels (when other factors, such as subsidies and other so-called externalities, are included, the price differential may not be so marked). The recent drop in oil prices has also exacerbated this difference in the short term, but in the long term may actually have little impact on renewable adoption, since the price of renewables is also decreasing.
According to the International Renewable Energy Authority (IRENA), the price of solar photovoltaic technology, for example, dropped by 70% from 2009-2013 (See Figure 1); prices have stabilised recently, but are expected to continue to decline. Commercial solar power has reached grid parity in countries such as Germany, Italy and Spain, with France due to attain parity soon. Some datacentres are responding to these price changes by acquiring grid-based renewables – either through power purchase agreements (as Google and Yahoo have done with local wind farms) or indirectly via RECs and other related instruments.
RECs – A renewable energy certificate is a tradable environmental commodity used to represent proof that one megawatt hour (MWh) of electricity was generated from a renewable source, such as a solar or wind farm. Each REC embodies the environmental and social benefits associated with generating its corresponding MWh of renewable electricity. A number of IT companies and datacentre operators have invested in RECs due to their accessibility. However, the certificates have also been criticised for effectively acting as environmental ‘indulgences,’ allowing an organisation to claim environmental responsibility by simply spending money, rather than actually changing its behaviour and buying less nonrenewable electricity. The limitations of RECs have led some companies, such as Google, to investigate alternative mechanisms, such as power purchase agreements, and even special renewable energy tariffs.
On-site renewables
Cost – The only way for a company to definitively prove that all of the energy for a facility is generated from renewables is for 100% of that energy to come from dedicated renewable generation – either on or close to the datacentre site. But even for companies with the financial resources of Google, Facebook and Apple, investing in on-site generation is costly and complex. Very few datacentres generate their own power for this reason. A 1MW wind turbine can cost from $1.3m-2.2m to build, while a new 1MW photovoltaic (PV) solar installation can cost roughly $1m-1.6m. Even if the power were reliable, or could be stored, the capex alone for one of these systems could be as much as 10-20% of the cost of a new datacentre (allowing for an alternative backup energy source). This is enough to make on-site renewable power generation impractical for many companies today.
Space – Space is also a problem. While the footprint of a wind turbine can be 1,000 sq. m or smaller, it requires a large open space to access the wind (and to comply with regulations). A 1MW solar plant typically requires five to six acres (2-2.4 hectares), which can easily be 10 times the size of a 1MW datacentre. Hyperscale operators aside, for many datacentres the land requirements for a solar or wind plant are simply unfeasible.
Storage – Effective use of on-site renewables also depends on having some form of energy storage, a nascent sector where most technologies are still expensive.
Design efficiency and power infrastructure – Effective use of on-site renewables is dependent on having an energy-efficient facility, and has implications for the overall design of the datacentre, and specifically the power infrastructure. Companies such as eBay or Apple that have adopted fuel cells, for example, have been able to simplify their power infrastructure and eliminate the need for backup mechanisms such as UPSs and diesel generators, in the belief that on-site energy generation is more reliable than relying on an external grid. In this scenario, on-site generation becomes the main source of power, with grid providing a backup if necessary.
Microgrids and colocation – One solutions is the colocation of datacentres close to solar plants. Examples include datacentre provider QTS, which built a facility in New Jersey adjacent to 57,000 solar panels generating up to 14.1MW of power. This could be viewed as a form of micro-grid between the solar power provider and datacentre – an approach that will increase in the future. It has even been proposed that datacentres should be colocated close to liquid natural gas terminals.
IT and workload management – Optimal use of renewables also requires IT hardware and software to be designed and managed effectively, including IT power management and other approaches. For example, certain classes of IT workloads can be time- or space-shifted (sent to neighbouring facilities) to maximise the availability of renewable energy (grid or on-site). This is probably most realistically achievable in non-mission-critical facilities and with non-time-sensitive workloads. For example, high-performance compute (HPC) facilities could make use of such approaches because they have more flexible service-level agreements and a relatively high proportion of workloads that could be time-shifted.
Toward the Net Zero Energy datacentre – Intelligent workload management, combined with the use of on-site renewables and other mechanisms, forms the basis of work done by HP and the European Union (451 Research is part of a consortium of organisations behind the EU-funded RenewIT project, which is investigating this area) around the concept of the Net Zero Energy datacentre. HP has demonstrated that its approach can cut total energy usage by 30%. The Net Zero Energy building is already a relatively established idea for other types of commercial facilities, with the aim of producing largely carbon-neutral structures. The concept of both Net Zero Energy buildings and datacentres is that the facility becomes essentially self-sufficient through the use of on-site generation and energy-efficiency techniques, as well as participation in micro-grids where energy and workloads can be transferred between small groups of interlinked facilities.
We will be keeping a watchful eye as energy pricing and regulations continue to change, and as we witness first hand the evolution of technologies to support the delivery and storage of renewable energy. Despite the present obstacles, an increasing number of operators see value in investing in renewables, and their actions may convince, or force, others to follow their lead.
